One of the tips on the linked page is to instruct the browser to use /tmp as its cache, after putting /tmp into RAM.Isn't that a bit dangerous? Surely that exposes the system to buffer overflows?I'm not knowledgable about such exploits so may have got the wrong end of the stick.

Then you do not need to do anything. If it is not like that then you can change the settings.Go to about:configSearch: cache.Set:browser.cache.memory.enable truebrowser.cache.disk.enable false (this may not be needed)